JP2017116860A - Method for forming optical fiber cable and optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable that can maintain the flexibility of a rope-like fiber member obtained by twisting a plurality of thread-like members, which is a tension member, and that can maintain the performance of an optical fiber line by suppressing generation of air bubbles in a coating layer, and to provide a method for forming the optical fiber cable.SOLUTION: In an aramid rope drying step (S2), an aramid rope prepared in an aramid rope preparation step (S1) is put in a vacuum state and is dried. Specifically, the aramid rope 2 is set in the inside of a vacuum drawing device (for example, a vacuum heater) and is dried by vacuum drawing with a specific degree of vacuum.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing an optical fiber cable including a nonmetallic tension member (hereinafter also referred to as a tension member), and an optical fiber cable including the nonmetallic tension member.

  Conventionally, it is known that an optical fiber cable is provided with a cable tension member called a “tension member” inside the cable in order to enhance the tension of the cable. There are various types of tension members, but there are also known members that constitute a tension member only with a tensile strength line.

  Since such a tensile wire requires strength, conventionally, a metal material such as a steel wire has been generally used. However, when a metal material is used for the tensile strength line, when an electric current flows undesirably in the tensile strength line due to lightning or the like, a device or the like breaks down, and information cannot be exchanged. That is, there is a possibility that information cannot be transmitted on the optical fiber line of the optical fiber cable.

  Therefore, in recent years, tension members using non-metallic (non-metallic) as tensile strength lines have been attracting attention and gradually increased. As this non-metallic, for example, it is known to use a fiber material such as glass fiber or carbon fiber, and a non-metallic tension member is constituted by impregnating the fiber material with a thermosetting resin composition. (Fiber Reinforced Plastics, FRP, etc.) are known.

  Moreover, in the tensile strength line | wire using such a fiber material, in order to raise intensity | strength, it can also be considered to comprise in a rope shape by twisting together several thread-like members.

  In addition, the manufacturing method described in the following patent document 1 is known as a manufacturing method which coat | covers coating materials, such as a resin composition, on such a rope-shaped member. This manufacturing method does not cover only the outer periphery of the rope-shaped member with a coating material such as a resin composition, but twists the thread-shaped member so that the coating material can be filled between the thread-shaped members (strand yarns). Immediately before, the coating material is extrusion coated. According to this manufacturing method, since there is no “gap” between the thread-like members in the rope, the problem that the cross-sectional shape of the rope loses its shape from a predetermined circular shape can be solved.

JP-A-61-102493

  By the way, an optical fiber cable is known in which a tensile strength line of a tension member and an optical fiber line are arranged in parallel and are collectively covered with a coating material such as a resin composition. In the coating operation in this case, the coating layer was formed by using a general technique such as extrusion coating.

  Therefore, it is conceivable to form a coating layer using a technique such as general extrusion coating as in the past even in the case where the fiber member configured in the above-described rope shape is used as a tensile strength line. It was found that an optical fiber cable similar to the conventional one cannot be obtained. Specifically, bubbles are generated in the coating layer, which may adversely affect the optical fiber line that is simultaneously coated.

  That is, when bubbles are generated in the coating layer, the position of the optical fiber line is deviated from a desired position, and the optical characteristics and mechanical characteristics are adversely affected.

  When the cause of this phenomenon is examined, when the fiber material is configured in a rope shape, moisture in the gaps in the fiber material is heated during the coating process to become water vapor, and the water vapor forms the coating layer. It is considered that during the formation, it cannot pass through the coating layer and remains as bubbles, or the optical fiber line is moved during the passage.

  As a countermeasure against this, it is conceivable that the gap in the fiber member is eliminated by extrusion coating the resin composition immediately before twisting the thread-like member as in the manufacturing method of Patent Document 1 described above. However, according to this method, there is a resin composition between each thread-like member, the flexibility of the fiber member as a rope is lost, and the bending resistance and twist resistance of the optical fiber cable are inferior. Another new problem will arise.

  Accordingly, the present invention provides an optical fiber cable in which a fiber member formed by twisting a plurality of thread members is used as a tension member, and optical fiber wires arranged in parallel with the tension member are collectively covered with a covering material. Optical fiber cable manufacturing method and optical fiber cable capable of maintaining performance of optical fiber cable while maintaining flexibility in fiber member while maintaining flexibility in fiber member in optical fiber cable An object is to provide a fiber cable.

  In the optical fiber cable manufacturing method of the present invention, the moisture remaining in the gaps in the fiber member is removed by evacuating the rope-like fiber member in the pre-process for extrusion coating the coating material such as the resin composition. This is a manufacturing method in which the generation of bubbles during the formation of the coating layer is prevented by removing the bubbles.

  Specifically, the first invention is a method of manufacturing an optical fiber cable in which an optical fiber line and a tension member are arranged in parallel inside and covered with a covering material, and a plurality of thread members are twisted together A member preparing step for preparing a fiber member in the form of a rope, a member moisture removing step for removing moisture from the fiber member obtained in the member preparing step to form a dry fiber member, and light using the dry fiber member as a tension member And a member covering step of covering the covering material with the fiber wire arranged in parallel.

  According to the said structure, the fiber member which twisted together the thread-like member in the member preparation process and was made into the rope shape was prepared, and then the water | moisture content was removed from the fiber member at the member water removal process, and a dry fiber member was obtained. Further, in the member coating step, the dry fiber member is arranged as a tension member in parallel with the optical fiber line, and is coated with a coating material such as a resin composition to manufacture an optical fiber cable. .

  That is, before coating the fiber member with a coating material such as a resin composition, the moisture present in the gaps in the fiber member is removed by the member moisture removal step, and the fiber member is dried (referred to as a dry fiber member). It is.

  For this reason, even if the fiber member is a rope formed by twisting a plurality of thread-like members, there will be no moisture in the dried fiber member (dry fiber member). When the dry fiber member and the optical fiber line are arranged in parallel and are collectively covered with the coating material, no bubbles are generated in the coating layer.

  Therefore, the possibility that the optical fiber line is adversely affected by the bubbles remaining in the coating layer can be eliminated.

  In addition, about the material of a fiber member here, organic fiber etc. can be considered besides glass fiber and carbon fiber, and it does not specifically limit. Moreover, although there is no limitation in particular also about how to twist, when twisting together in the shape of a rope, it is preferable to twist together by various twists.

  As for the coating material, a resin composition in which a plasticizer or a flame retardant is blended with a resin, a rubber composition in which a plasticizer or a flame retardant is blended in rubber, or a plasticizer or flame retardant is blended in an elastomer. It may be a composition.

  Here, the optical fiber line is a general term for an optical fiber core wire, an optical fiber cord, and the like, and an optical fiber core wire or an optical fiber cord may be applied as the optical fiber line.

  A second invention is the manufacturing method according to the first invention, wherein the member moisture removing step is a member drying step in which the fiber member is dried in a vacuum state.

  According to the above configuration, the member moisture removing step is a member drying step in which the fiber member is placed in a vacuum state to dry, and using the vacuum state, the moisture present in the gap in the fiber member is sucked out, The fiber member is evaporated in a vacuum to dry (remove moisture).

  Thereby, in the method of removing moisture such as heat evaporation, it is possible to reliably perform even moisture removal inside the difficult fiber member.

  Therefore, moisture removal inside the fiber member can be performed more reliably.

  3rd invention is a manufacturing method characterized by heating the said fiber member simultaneously in the said member drying process in 2nd invention.

  According to the said structure, by removing a fiber member only by evacuation only by heating a fiber member simultaneously at a member drying process, a water | moisture content can be removed earlier. That is, although the boiling point temperature of water decreases in a vacuum state, the boiling of moisture is further promoted by heating, and the moisture in the fiber member is more easily removed.

  Therefore, since the moisture in the fiber member can be removed earlier in the member drying process, the increase in manufacturing time due to newly setting the member drying process can be reduced as much as possible, and the manufacturing tact and manufacturing cost can be reduced. Can be suppressed as much as possible.

  4th invention WHEREIN: In any 1st thru | or 3rd invention, immediately before the said member covering | coating process, the member heating process of heating this fiber member so that the water | moisture content of the surface of the said fiber member may be removed. It is the manufacturing method characterized by having provided.

  According to the above configuration, since the member heating step is provided, the fiber member is further heated immediately before the member covering step. For this reason, the water | moisture content adhering to the fiber member surface can be removed reliably.

  That is, even if it is a fiber member (dried fiber member) dried in the member drying step, moisture is immediately attached to the surface of the fiber member due to the humidity (humidity) of the outside air when touching the outside air. In order to remove this, heating is performed in the member heating step.

  Therefore, by setting the member heating process, the moisture in the fiber member is removed in the member drying process, and the moisture that easily adheres to the surface of the fiber member is reliably removed in the member heating process. The problem that bubbles are generated in the coating layer during the coating process can be prevented more reliably.

  A fifth invention is the manufacturing method according to any one of the first to fourth inventions, wherein the fiber member is an aramid fiber.

  According to the said structure, since the fiber member is an aramid fiber, the water | moisture content inside the filamentous member which exists by the moisture retention of an aramid fiber can be more reliably removed using a vacuum state.

  For this reason, even if it is an aramid fiber excellent in flexibility, even the moisture present inside the thread-like member can be completely removed. Can be completely prevented.

  Therefore, it is possible to manufacture an optical fiber cable that does not generate bubbles in the coating layer while maintaining the higher flexibility unique to the aramid fiber.

  A sixth invention is an optical fiber cable in which an optical fiber line and a tension member are arranged in parallel inside and covered with a covering material, and the tension member is formed by a rope formed by twisting a plurality of thread members. The optical fiber cable is composed of a dry fiber member having a moisture content smaller than the standard moisture content under atmospheric pressure.

  Here, the moisture content of the dry fiber member should be less than the standard moisture content of the fiber member under atmospheric pressure, and the moisture content is such that no bubbles are generated when the coating material is coated. For example, there is no particular limitation.

  For example, specifically, in the case of aramid fiber, the standard water content under atmospheric pressure is 4% by weight or more and 6% by weight or less. In the case of a dry aramid rope obtained by drying this aramid fiber Is set to 0.5 wt% or more and 1.5 wt% or less (moisture removal condition: 80 ° C. × 48 hours, a value measured immediately after evacuation to −76 cmHg). It is possible.

  In addition, this moisture content is the value which measured the generated moisture content at the time of 140 degreeC heating with a Karl Fischer moisture meter. And the measuring instrument used the CA200 type | mold trace moisture measuring apparatus by Mitsubishi Chemical Analytech, and VA-200 type | mold (The sample amount used for the measurement is 0.15-0.20g, and measured arbitrary 1 points | pieces, The variation in the moisture content is about ± 0.05% by weight).

  According to the above configuration, the tension member is composed of a dry fiber member having a moisture content less than the standard moisture content of the fiber member at atmospheric pressure, so that the covering member such as a resin composition can be used. Even when the dry fiber member is heated during coating, no water vapor or the like is generated, so that no bubbles remain in the coating layer.

  Therefore, since it is possible to eliminate the adverse effects of bubbles remaining on the optical fiber line inside the cable, the fibers can be maintained while maintaining the flexibility of the fiber member, so that no bubbles remain in the coating layer. Performance can be maintained.

  In a seventh aspect based on the sixth aspect, the optical fiber line is disposed at an inner central position, and the two dry fiber members are disposed in parallel at both outer positions of the optical fiber line. An optical fiber cable.

  According to the above configuration, the optical fiber line is arranged at the center position, and the two dry fiber members are arranged in parallel at both outer positions of the optical fiber line, so that, for example, a connector is attached to the end of the optical fiber cable. Even when the dry fiber member at both sides is gripped and tension is applied, there is no air bubble in the cable, so that an equal tension can be applied to the optical fiber cable.

  That is, if air bubbles are present in the cable, the optical fiber line is locally distorted, which may adversely affect the optical fiber, and may adversely affect the mechanical characteristics of the optical fiber cable. There is.

  Therefore, by devising the arrangement relationship between the optical fiber line inside the cable and the dry fiber member, the optical characteristics and mechanical characteristics of the optical fiber cable can be maintained without the influence of air bubbles.

  In an eighth aspect based on the seventh aspect, the optical fiber line is composed of two optical fibers arranged in parallel with each other at a central position, and the outer surface of the covering material is provided with the two optical fiber lines. An optical fiber cable characterized in that a notch portion for jacket tearing is formed at a position corresponding to the gap.

  According to the above configuration, it is possible to easily perform the end processing of the optical fiber cable by providing the notch portion for the outer shell tearing for the end processing of the optical fiber cable (processing for mounting the connecting connector or the like). Instead, the terminal processing at this time can be performed more reliably and easily.

  In other words, if the position of the optical fiber line in the cable is not stable and linear, the position of the notch part and the optical fiber line will be misaligned, and when the coating layer is torn at the position of the notch part, There is a possibility that the breaking operation cannot be performed smoothly due to the fiber line. However, since the optical fiber line is not affected by bubbles, the optical fiber line is positioned in a straight line, and the tearing operation of the coating layer can be performed reliably and easily.

  Therefore, by forming a notch for tearing the jacket on the outer surface of the covering material, the end treatment of the optical fiber cable can be easily performed, and at the same time, the positional deviation between the notch and the optical fiber line does not occur. Therefore, the end processing of the optical fiber cable can be reliably and smoothly performed.

  According to the present invention, even if the fiber member is a rope formed by twisting a plurality of thread-like members, moisture does not exist in the fiber member (dry fiber member), so in the member coating step, When the fiber member and the optical fiber line are arranged in parallel and covered with a covering material, no bubbles are generated in the covering layer.

  For this reason, the possibility that the optical fiber line is adversely affected by the bubbles remaining in the coating layer can be eliminated.

  Therefore, a fiber member that is formed by twisting a plurality of thread-like members into a rope member as a tension member, and an optical fiber cable that covers an optical fiber line arranged in parallel with the tension member with a covering material, and In the optical fiber cable, it is possible to obtain an optical fiber cable that maintains the performance of the optical fiber line by maintaining the flexibility of the fiber member and preventing the generation of bubbles in the coating layer.

It is a flowchart figure which shows the manufacturing process of the optical fiber cable concerning embodiment of this invention. It is a detailed cross-sectional view of the optical fiber cable of the present invention. 1 is an overall cross-sectional view of an optical fiber cable of the present invention. It is a cross-sectional view of the optical fiber cable when not manufactured by the manufacturing method of the present invention. It is the VV sectional view taken on the line of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  It should be noted that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a flowchart showing an optical fiber cable manufacturing process W according to an embodiment of the present invention. FIG. 2 is a detailed cross-sectional view of the optical fiber cable of the present invention manufactured by the manufacturing method. FIG. 3 is an overall cross-sectional view of the optical fiber cable.

  As shown in the flowchart of FIG. 1, the optical fiber cable manufacturing process W is roughly divided into a tension member manufacturing process W1 for manufacturing the tension member 1, an optical fiber line manufacturing process W2 for manufacturing an optical fiber line, and these. The tension member 1 and the optical fiber cable completion process W3 completed by assembling the optical fiber wires are provided.

  Hereinafter, these steps will be described in order.

(Tension member manufacturing process W1)
First, the tension member manufacturing process W1 includes an aramid rope preparation process S1 as a member preparation process, an aramid rope drying process S2 as a member moisture removal process, or a member drying process, and an aramid rope heating process immediately before a member. S3.

  In the aramid rope preparation step S1, a plurality of thread-like members 2a to 2d (see FIG. 2), each of which is an independent aramid fiber, are twisted together in a rope shape by rope twisting, specifically, various twists, or already Aramid rope 2 (in FIG. 2, aramid in a dry state) is purchased by using commercially available aramid rope 2 (for example, Kepler rope, etc .: “Kepler” is a registered trademark of DuPont). Rope 2A: Hereinafter, dry aramid rope 2A) is prepared. For example, it is conceivable to prepare an aramid rope 2 by purchasing an aramid rope 2 having a thickness of about 1.7 mm of 1670 dtex × 3 × 4 marketed as “Kepler rope”. The fineness (dtex) of the aramid rope 2 is not particularly limited as long as it is 120 dtex or more.

  The aramid rope 2 thus prepared is subjected to terminal processing in advance. Specifically, the ends of the aramid rope 2 are collectively covered with an adhesive or are fixed together with a cylindrical heat-shrinkable tube. By performing such terminal processing, it becomes easy to put into the extrusion device in the cable assembly covering step S5 described later.

  Next, in the aramid rope drying step S2, the aramid rope 2 prepared in the aramid rope preparation step S1 is placed in a vacuum state and dried. Specifically, the aramid rope 2 is installed inside an apparatus (for example, a vacuum heater) that performs evacuation, and evacuation is performed at a predetermined degree of vacuum inside the apparatus to dry the aramid rope 2. In this way, dry aramid rope 2A as a dry fiber member is obtained. This dried aramid rope 2A becomes the tension member 1 of the optical fiber cable C1.

  The drying of the aramid rope 2 is performed by degassing the air inside the aramid rope 2, specifically, the “gap” of each twisted thread-like member (2 a to 2 d), and the moisture inside the aramid rope 2 in a vacuum. Evaporated and removed as water vapor. Furthermore, although the aramid rope 2 is composed of an aramid fiber, the moisture held by the fiber itself is removed by evacuation due to the moisture retention of the aramid fiber.

  In this aramid rope drying step S2, heating is also performed at a predetermined temperature simultaneously with evacuation. Thus, by heating, the moisture temperature in the aramid rope 2 is increased to facilitate evaporation as water vapor, and the dried aramid rope 2A is obtained at an early stage.

  In other words, water boils at a temperature lower than 100 ° C., which is the boiling point of atmospheric pressure under vacuum, but by performing such heating, the water is changed to water vapor at an earlier stage than when simply evacuated. It can be removed.

  The aramid rope drying step S2 is preferably performed under drying conditions of, for example, a vacuum degree of −76 cmHg, a heating temperature of 80 ° C., and a process holding time of 48 hours. However, this is an example of suitable drying conditions, and is not limited thereto.

  About heating temperature here, what is necessary is just the range of 50 to 120 degreeC. If this temperature range is less than 50 ° C., moisture tends not to be removed at an early stage, and if it exceeds 120 ° C., aramid fibers tend to be damaged by heat. That is, by raising the temperature by heating, the drying time of the aramid rope 2 can be shortened as described above. However, if the temperature is too high, the aramid fibers are thermally damaged, and the tensile properties as the tension member 1 are increased. This tends to lower the value. Therefore, it is more desirable to perform heating in such a temperature range.

  Further, the process holding time may be in the range of 5 hours to 100 hours. Regarding the process holding time, the aramid rope 2 can be reliably dried by holding the vacuum state for a certain time or longer, but the drying state of the dried aramid rope 2A does not change even if it is longer than necessary. Therefore, it is desirable to set the process holding time.

  Furthermore, the degree of vacuum for evacuation may be made closer to the vacuum with a negative pressure that is gentler than the aforementioned -76 cmHg. In other words, the pressure may be lower than the atmospheric pressure (negative pressure) and a degree of vacuum that removes moisture in the aramid rope 2 may be applied.

  In the present embodiment, the aramid rope drying step S2 is performed by evacuating the individual aramid ropes 2 by placing them inside the apparatus that performs evacuation. Among them, the aramid rope 2 may be continuously evacuated. By doing so, the manufacturing time can be greatly shortened, and mass production is also possible.

  Next, in the heating step S3 immediately before the aramid rope, after the dried aramid rope 2A obtained in the aramid rope drying step S2 is taken out from the vacuum space (immediately before the cable assembly coating step S5 described later), a high-temperature heating device (for example, Heating through a drying heater). This is because the moisture adhering to the surface of the dried aramid rope 2A is removed by heating at once. That is, when the dry aramid rope 2A once touches the outside air during the cable assembly coating step S5 described later from the aramid rope drying step S2 described above, the humidity of the outside air adheres to the surface of the dried aramid rope 2A as moisture, Since the adhering water may cause bubbles, the water adhering to the surface of the dry aramid rope 2A is heated and removed by the heating device as much as possible as water vapor.

  This heating step S3 immediately before the aramid rope is performed, for example, by passing the dried aramid rope 2A through a heating device heated to 250 ° C. The heating temperature may be any temperature as long as moisture on the surface of the dried aramid rope 2A can be removed by drying.

  The heating step S3 immediately before the aramid rope is, as described above, the time and environment (humidity, etc.) related to the cable assembly coating step S5 described later from the aramid rope drying step S2 (for example, the time and environment until setting in the extrusion device) (Humidity etc.)) may be unnecessary.

  By obtaining the dry aramid rope 2A as described above, the tension member 1 of the optical fiber cable C1 is manufactured.

(Optical fiber manufacturing process W2)
Next, the optical fiber line manufacturing process W2 will be described. The optical fiber line manufacturing process W2 includes a known optical fiber line manufacturing process S4. Specifically, for example, a step of forming a cladding on the outer periphery of the core, an optical fiber core manufacturing step of forming a primary coating layer on the outer periphery of the cladding, or a secondary coating layer further on the outer periphery of the optical fiber core wire There is an optical fiber cord manufacturing process or the like.

  In addition, an ultraviolet curable resin composition is applied to the primary coating layer, and a polyester resin composition, a polyvinyl chloride resin composition, a non-halogen resin composition, or the like is applied as the secondary coating layer.

  In this optical fiber line manufacturing process W2, a plurality of optical fiber lines 3 are manufactured to prepare for the next process.

(Optical fiber cable completion process W3)
Next, the optical fiber cable completion process W3 will be described. The optical fiber cable completion process W3 includes a cable assembly covering process S5.

  In this cable assembly covering step S5, two optical fiber lines 3 and 3 are arranged in parallel at the center position, and dry aramid ropes 2A and 2A, that is, two tension members 1 and 1 are disposed at outer positions on both sides thereof. Place each one. Thus, the optical fiber lines 3 and 3 and the dried aramid ropes 2A and 2A are collectively arranged. The position of the collective arrangement determines the positional relationship between the two optical fiber lines 3 and 3 and the two dry aramid ropes 2A and 2A when the optical fiber cable C1 is completed.

  And the resin composition 6 which is a coating | coated material is extruded and coat | covered by a resin extrusion apparatus so that the outer peripheral position of this optical fiber line 3 and 3 and dry aramid rope 2A, 2A may be surrounded. Thereby, the optical fiber cable C1 is manufactured. The covering shape (die shape) at this time is, for example, a flat shape having a horizontally long and substantially rectangular cross section as shown in FIG.

  The resin composition 6 extruded here is, for example, a resin composition in which a plasticizer or a flame retardant is blended with polyethylene or polyvinyl chloride. As the conditions for extrusion coating of these resin compositions 6, known ones may be applied.

  In addition, as the resin composition 6 to be extruded, a non-halogen resin composition (for example, polyolefin (polyethylene, ethylene / ethyl acrylate (EEA), etc.) made of a material not containing a halogen element is used as a base resin, and a flame retardant. (Magnesium hydroxide surface-treated with magnesium hydroxide, fatty acid, etc.) and other non-halo resin compositions composed of other compounding agents (phosphorus compounds) may be applied. Further, instead of the resin composition 6, a rubber composition or an elastomer composition may be applied.

  Thus, the so-called flat optical fiber cable C1 is completed by covering the optical fiber lines 3 and 3 and the dried aramid ropes 2A and 2A with the resin composition 6.

  Then, in the final finished product inspection step S6, it is inspected whether the appearance, structure, optical characteristics and the like of the thus completed optical fiber cable C1 are appropriate. The optical fiber cable C1 that has passed the inspection in the finished product inspection step S6 is shipped to the market.

  An example of the finished product manufactured in this way is the optical fiber cable C1 of FIG. As described above, the optical fiber cable C1 is a so-called flat-type optical fiber cable C1, and is an optical fiber cable having a horizontally long and substantially rectangular cross-sectional shape.

  The flat-shaped optical fiber cable C1 is an optical fiber cable that can stably transmit information even when reciprocating in a specific direction while maintaining a state of a constant bending radius. Used for OA equipment such as copying machines, and cables for elevators and the like.

  In this optical fiber cable C1, two optical fiber lines 3 and 3 are arranged adjacent to each other at the center of the cable, and dried aramid ropes 2A and 2A one at a time on both sides on the outer side of the cable. The tension members 1 and 1 are arranged. And the coating layer 6 which consists of the resin composition 6 is located in those circumference | surroundings.

  And the substantially V-shaped notch parts 7 and 7 are formed in the upper surface 6a and the lower surface 6b of the outer peripheral surface of this coating layer 6. FIG. The notches 7 are formed simultaneously with the extrusion molding of the coating layer 6. These notch portions 7 and 7 are formed at positions corresponding to exactly between the two optical fiber lines 3 and 3 (center position of the code C1), and the covering layer 6 is torn off from the notch portions 7 and 7 as starting points. This facilitates terminal processing such as connector mounting.

  Further, as described above, the tension member 1 is constituted by the dried aramid rope 2A obtained through the aramid rope drying step S2 and the like. As shown in FIG. 2, this dry aramid rope 2A is formed as a rope by twisting four thread members 2a, 2b, 2c, 2d with various twists, but this outer peripheral shape 20 is uneven. It has an irregular shape that is closer to a quadrangle than a circle. This is because, in the aramid rope drying step S2, the aramid rope 2 is evacuated to completely dry the aramid rope 2.

  That is, by drying the aramid rope 2, there is no gap between the four thread members 2a, 2b, 2c, and 2d, and the thread members 2a, 2b, 2c, and 2d are in close contact with each other, This is because the boundary lines 21a, 21b, 21c, and 21d simply exist between the respective thread members 2a, 2b, 2c, and 2d.

  As described above, since the aramid rope 2 is evacuated to the dry aramid rope 2A, there is no gap inside the dry aramid rope 2A, and there is no moisture contained in the gap. In the coating process, no bubbles remain in the coating layer 6.

  Further, since the outer peripheral shape 20 of the tension member 1 made of the dried aramid rope 2A has an irregular shape close to a quadrangle, the boundary line 22 with the coating layer 6 is not a circular shape but an irregular shape close to a quadrangle. It becomes. For this reason, even if the strength in the rotational direction (circumferential direction) between the tension member 1 and the covering layer 6 increases and a load in the torsional rotational direction acts repeatedly on the tension member 1, the tension member 1 and the covering layer 6 There will be no separation between the two.

  Therefore, since the adhesion between the tension member 1 and the covering layer 6 can be maintained for a long time, the flexibility (twisting resistance and bending resistance) and durability of the optical fiber cable C1 can be maintained at a high level.

  If the coating layer 6 is extrusion molded in a state where moisture in the aramid rope 2 is not removed, that is, in the case of the conventional manufacturing method without the aramid rope drying step S2, FIG. 4 and FIG. The phenomenon shown will occur.

  4 is a cross-sectional view of an optical fiber cable manufactured by a conventional manufacturing method, and FIG. 5 is a cross-sectional view taken along the line VV of FIG.

  When the optical fiber cable C10 is manufactured by the conventional manufacturing method, a phenomenon occurs in which a plurality of cavities 11 and bubbles 12 appear in the coating layer 6 and on the surface as shown in the drawing.

  This is because when the resin composition 6 is extrusion-coated, moisture (water vapor) in the aramid rope 2 heated by the high-temperature resin composition 6 is ejected from the inside of the aramid rope 2 and the inside or surface of the coating layer 6 In addition, it is considered that they remain as cavities 11 and bubbles 12.

  Thus, if bubbles 12... Remain on the surface of the coating layer 6 of the optical fiber cable C11, the appearance of the surface of the optical fiber cable C10 is poor and the dimensions are deviated.

  Further, when the cavities 11 are formed inside the coating layer 6, the optical fiber line 3 inside the coating layer 6 is pushed by the cavity and deviates from the center of the cable in the left-right direction (see FIG. 4). Since the location and size where the cavities 11 can be formed cannot be predicted at all, as shown in FIG. 5, the two optical fiber lines 3 and 3 are arranged in the left-right direction (in the drawing, in the horizontal direction). It is positioned to meander in the vertical direction.

  For this reason, after the coating layer 6 is extruded and coated, the optical fiber lines 3 and 3 are meandering even in a normal state, so that the optical fiber lines 3 and 3 are always bent and are always loaded, and the optical characteristics. May decrease.

  In FIG. 5, a line X extending in the left-right direction at the center position of the cable indicated by a two-dot chain line indicates the position where the notch portions 7 and 7 are formed. When 3 meanders, a position shift occurs in the left-right direction between the position (X) of the notch portions 7 and 7 and the position of the optical fiber lines 3 and 3.

  As described above, when the optical fiber lines 3 and 3 and the notch portions 7 and 7 are misaligned, the optical fiber lines 3 and 3 are obstructed when the coating layer 6 is torn from the notch portions 7 and 7. And there arises a problem that it becomes difficult to tear.

  In the manufacturing method of the present embodiment, the aramid rope drying step S2 is set, and the dry aramid rope 2A from which the moisture in the aramid rope 2 is removed is configured as the tension member 1 with respect to the above problems. Does not occur.

  That is, in this embodiment, in the manufacturing method of the optical fiber cable C1 in which the optical fiber wires 3 and 3 and the tension members 1 and 1 are arranged in parallel inside the cable and covered with the resin composition 6, the aramid rope 2 An aramid rope drying step S <b> 2 is provided to remove moisture and make a dry aramid rope 2 </ b> A.

  For this reason, even if the tension member 1 is configured with the aramid rope 2 formed by twisting a plurality of thread-like members 2a, 2b, 2c, and 2d, there is no moisture in the dry aramid rope 2A. Even if it is coated with the resin composition 6 in the cable assembly coating step S5, the bubbles 11 do not remain in the coating layer 6.

  Therefore, the possibility that the optical fiber lines 3 and 3 are adversely affected by the bubbles 11 remaining in the coating layer 6 can be eliminated.

  Therefore, in the manufacturing method of the optical fiber cable C1 in which the aramid rope 2 is used as the tension member 1 and the optical fiber wire 3 arranged in parallel with the tension member 1 is collectively covered with the resin composition 6, the flexibility of the aramid rope 2 is improved. The performance of the optical fiber line 3 can be maintained while maintaining.

  Moreover, in this embodiment, aramid rope drying process S2 is a drying process by the vacuum drawing which puts the aramid rope 2 in a vacuum state and performs drying.

  With this configuration, using the vacuum state, moisture present in the gaps in the aramid rope 2 is sucked out and evaporated in the vacuum, and the aramid rope 2 is dried (moisture removal).

  Thereby, in the method of removing moisture such as heat evaporation, it is possible to reliably perform even moisture removal inside the difficult fiber member.

  Therefore, it is possible to more reliably perform the removal of moisture inside the aramid rope 2.

  In the present embodiment, the aramid rope 2 is simultaneously heated in the aramid rope drying step S2.

  With this configuration, moisture can be further removed in a shorter time than drying by vacuuming alone.

  Therefore, an increase in manufacturing time due to the newly set aramid rope drying step S2 can be reduced as much as possible, and an increase in manufacturing tact and manufacturing cost can be suppressed as much as possible.

  In this embodiment, immediately before the cable assembly covering step S5, an aramid rope immediately heating step S3 for heating the dried aramid rope 2A so as to remove moisture on the surface of the dried aramid rope 2A is provided.

  With this configuration, since the dried aramid rope 2A is further heated immediately before the cable assembly covering step S5, moisture adhering to the surface of the dried aramid rope 2A can be reliably removed.

  Therefore, since moisture that easily adheres to the surface of the dried aramid rope 2A can be reliably removed, the problem that air bubbles are generated and remain in the coating layer 6 during the cable assembly coating step S5 is more reliably prevented. Can be prevented.

  Moreover, in this embodiment, the tension member 1 is comprised with the aramid rope 2 comprised with an aramid fiber.

  With this configuration, moisture inside the thread-like members 2a, 2b, 2c, and 2d that exists due to the moisture retention of the aramid fibers can be more reliably removed using a vacuum state.

  For this reason, even if the tension member 1 is composed of an aramid fiber excellent in flexibility, moisture existing inside the fiber can be removed, so that the formation of cavities 11 and bubbles 12 in the coating layer 6 can be prevented.

  Therefore, it is possible to manufacture the optical fiber cable C1 in which the cavity 11 and the bubbles 12 are not generated and remain in the coating layer 6 while maintaining the higher flexibility unique to the aramid fiber.

  Furthermore, this embodiment is an optical fiber cable C1 in which the optical fiber wires 3 and 3 and the tension members 1 and 1 are arranged in parallel inside the cable and covered with the covering layer 6, and the tension members 1 and 1 Is composed of dried aramid ropes 2A and 2A having a retained moisture amount smaller than the standard retained moisture amount under atmospheric pressure.

  For example, the standard water content of atmospheric aramid fibers under atmospheric pressure is 4.2% by weight, but the water content of these dry aramid ropes 2A and 2A is 1.2% by weight (water removal conditions: It is set to (measured promptly after evacuating to -76 cmHg at 80 ° C. for 48 hours).

  The amount of water is a value obtained by measuring the amount of water generated during heating at 140 ° C. with a Karl Fischer moisture meter. And the apparatus used for the measurement used the CA200 type | mold trace moisture measuring apparatus by Mitsubishi Chemical Analytech, and the VA-200 type | mold moisture vaporizer (The sample amount used for the measurement is 0.15-0.20g, arbitrary. 1 point is measured, the variation in water content is about ± 0.05%).

  With this configuration, even when the dry aramid rope 2A is heated when the resin composition 6 is coated, almost no water vapor or the like is generated, so that the cavity 11 and the bubbles 12 do not remain in the coating layer 6.

  Therefore, since the bad influence by the cavity 11 and the bubble 12 remaining with respect to the optical fiber lines 3 and 3 can be eliminated, the performance of the optical fiber line 3 was maintained while maintaining the flexibility of the aramid rope 2. An optical fiber cable C1 can be obtained.

  Further, in this embodiment, the optical fiber lines 3 and 3 are arranged at the central position inside the cable, and the two dry aramid ropes 2A and 2A are arranged in parallel at both outer positions of the optical fiber lines 3 and 3, respectively. Has been placed.

  With this configuration, even if water vapor or the like is generated from the dried aramid rope 2A and the cavities 11 and bubbles 12 remain, the dried aramid rope 2A, Since 2A is located, the influence of the cavity 11 and the bubble 12 is less likely to occur in the optical fiber lines 3 and 3.

  That is, since no bubbles remain, the mechanical characteristics and optical characteristics of the optical fiber cable are not deteriorated, and a decrease in yield due to poor appearance can be suppressed.

  Moreover, in this embodiment, the optical fiber lines 3 and 3 are comprised by the two extended in parallel in a center position, and these two optical fiber lines 3 and 6 are formed in the outer surfaces 6a and 6b of the coating layer 6. FIG. 3, notch portions 7 and 7 for tearing the jacket are formed at positions corresponding to each other.

  With this configuration, the end processing of the optical fiber cable C1 can be performed more reliably and easily.

  That is, since the optical fiber lines 3 and 3 are stabilized in a straight line, there is no positional deviation between the notch portions 7 and 7 and the optical fiber lines 3 and 3. When tearing 6, the operation of tearing the coating layer 6 can be performed reliably and easily without the optical fiber lines 3 and 3 getting in the way.

  Therefore, by forming the notch portions 7 and 7 for the outer shell tearing on the outer surfaces 6a and 6b of the covering material 6, the end treatment of the optical fiber cable C1 can be easily performed, and at the same time the notch portions 7 and 7 and Since the positional deviation with respect to the optical fiber lines 3 and 3 does not occur, the end processing of the optical fiber cable C1 can be performed reliably and smoothly.

  Although the present invention has been described above with the two-fiber type flat optical fiber cable C1, the present invention is not limited to this embodiment. For example, you may implement with manufacturing methods and structures, such as a 1 core type flat type optical fiber cable (optical fiber cable comprised by one optical fiber wire and one tension member). That is, any structure may be used as long as the optical fiber cable C1 is manufactured by a coating process in which the optical fiber wire 3 and the tension member 1 are arranged in parallel and covered together.

  Further, the resin composition of the coating layer 6 is not particularly limited as long as it is extrusion-coated.

  Further, the tension member 1 is not particularly limited to the aramid rope 2 as long as it is formed by twisting a fibrous thread-like member into a rope shape. For example, if the fiber member is formed by twisting a plurality of thread-like members such as carbon fiber, glass fiber, organic fiber, etc., a gap is formed inside the fiber member, so that the effect of the present invention can be obtained. .

  As described above, the present invention uses, for example, a fiber member configured as a rope by twisting a plurality of thread-like members as a tension member, and a method for manufacturing an optical fiber cable that covers optical fiber wires collectively, And useful in fiber optic cables.

W ... Optical fiber cable manufacturing process W1 ... Tension member manufacturing process W2 ... Optical fiber wire manufacturing process W3 ... Optical fiber cable completion process S1 ... Aramid rope preparation process (member preparation process)
S2 ... Aramid rope drying process (member moisture removal process, member drying process)
S3 ... heating process immediately before aramid rope (heating process immediately before member)
S5: Cable assembly coating process (member coating process)
C1 ... Optical fiber cable 1 ... Tension member 2 ... Aramid rope 2A ... Dry aramid ropes 2a, 2b, 2c, 2d ... Thread member (aramid fiber)
3 ... Optical fiber 6 ... Coating layer (resin composition, coating material)
7 ... Notch

Claims (8)

An optical fiber cable and a tension member are arranged in parallel inside, and a manufacturing method of an optical fiber cable covered with a covering material,
A member preparation step of preparing a fiber member made into a rope shape by twisting a plurality of thread-like members;
A member moisture removing step of removing moisture from the fiber member obtained in the member preparing step to obtain a dry fiber member;
A member covering step of arranging the dry fiber member as a tension member in parallel with the optical fiber line and covering the covering;
An optical fiber cable manufacturing method comprising: 2. The optical fiber cable manufacturing method according to claim 1, wherein the member moisture removing step is a member drying step in which the fiber member is dried in a vacuum state. 3. The method of manufacturing an optical fiber cable according to claim 2, wherein the fiber member is heated simultaneously in the member drying step. The optical fiber according to any one of claims 1 to 3, further comprising a member heating step of heating the fiber member so as to remove moisture on a surface of the fiber member immediately before the member covering step. Cable manufacturing method. The method for manufacturing an optical fiber cable according to claim 1, wherein the fiber member is an aramid fiber. An optical fiber cable in which an optical fiber line and a tension member are arranged in parallel and covered with a covering material,
The tension member is formed of a dry fiber member in which a plurality of thread-like members are twisted together to form a rope, and the moisture content is smaller than the standard moisture content under atmospheric pressure. cable. 7. The light according to claim 6, wherein the optical fiber line is disposed at an inner central position, and the two dry fiber members are disposed in parallel at both outer positions of the optical fiber line. Fiber cable. The optical fiber line is composed of two fibers arranged in parallel with each other at a central position, and the outer surface of the covering material is used for tearing the outer cover at a position corresponding to the space between the two optical fiber lines. The optical fiber cable according to claim 7, wherein a notch is formed.

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